Re: FTS phrase searches

You might be interested in http://www.sai.msu.su/~megera/wiki/2009-08-12

Oleg
On Sun, 19 Dec 2010, Glenn Maynard wrote:

> I guess no response means it's not possible.  I ended up doing a
> manual substring match for quoted strings, but that's a poor hack.
> Maybe I'll take a poke at implementing something like
> tsvector_contains_phrase; it seems like a natural extension of what's
> in there now.
>
>
> On Mon, Nov 1, 2010 at 4:35 PM, Glenn Maynard <glenn@zewt.org> wrote:
>> How are adjacent word searches handled with FTS?  tsquery doesn't do
>> this, so I assume this has to be done as a separate filter step, eg.:
>>
>>  # "large house" sales
>>  SELECT * FROM data WHERE fts @@ to_tsquery('large & house & sales')
>> AND tsvector_contains_phrase(fts, to_tsvector('large house')));
>>
>> to do an indexed search for "large & house & sales" and then to narrow
>> the results to where "large house" actually appears as a phrase (eg.
>> adjacent positions at the same weight).  I can't find any function to
>> do that, though.  (Presumably, it would return true if all of the
>> words in the second tsvector exist in the first, with the same
>> positions relative to each other.)
>>
>> "tsvector <@ tsvector" seems logical, but isn't supported.
>>
>> This isn't as simple as using LIKE, since that'll ignore stemming,
>> tokenization rules, etc.  If the language rules allow this to match
>> "larger house" or "large-house", then a phrase restriction should,
>> too.  It's also painful when the FTS column is an aggregate of several
>> other columns (eg. title and body), since a LIKE match needs to know
>> that and check all of them separately.
>>
>> Any hints?  This is pretty important to even simpler search systems.
>
>

     Regards,
         Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83